1. Field of the Invention
The present invention relates generally to valve seat assemblies for various not limited to such as check valve and pressure relief applications. More specifically, the present invention discloses a novel and unique one-piece combined spring and poppet, such as which is produced by a helically turned piece of material, the one-piece design providing improved performance and reduced incidence of breakage as compared to prior art and multi-piece spring and poppet assemblies.
2. Description of the Prior Art
The prior art is well documented with various types of valve configurations, including most notably those incorporated into check and pressure relief valve assemblies. A first example of a valve assembly incorporating a plasticized poppet is disclosed in Scholle et al., U.S. Pat. No. 5,255,713, and which includes a central disc part and tapered flange for engaging a valve seat. A plurality of three integrally formed beams extends from the disc portion and is received in an annular groove defined in an inner wall of the valve body. The integrally formed beams act as biasing leaf springs providing a resilient force to bias the poppet in a closed position. In this assembly, the valve unit is constructed of two pieces including a plastic valve and the internally displaceable poppet and leaf springs.
Another reference of note is disclosed in U.S. Pat. No. 3,626,977, issued to Riley, and which teaches a combination check and pressure relief valve in which a lightweight poppet valve member is held closed by a calibrated spring and supplemented by a floating self-aligning resilient O-ring seal held against dilation by an encircling channel-shaped retainer ring. Of note, the poppet and O-ring are held captive by a one-piece cage permanently assembled between the surrounding valve housing components welded seams, the cage being contoured to provide separate stops for the poppet and the O-ring retainer unit.
U.S. Pat. No. 5,332,000, issued to Glassner, teaches a close tolerance fluid pressure relief or check valve (low pressure sensitive valve) including a one-piece silicone poppet within a valve body. The poppet makes line contact with a concave seat surface at the inlet end of the body when the poppet is closed. A stem of the poppet extends into an inlet passage of the body to guide poppet movement centrally between open and closed positions. The poppet is biased to its closed position by a spring within the body, the pressure setting of which is controlled by a threaded nut or fitting defining an outlet passage and closing the outlet end of the body.
Another reference of interest is set forth in PCT/WO application No. 86/00681, to Brunswick Valve and Control, Inc., and which teaches an in-line check valve having combined downstream poppet support and flow control elements. The poppet-type check valve utilizes an integral detachable flow control assembly for insertion into a cooperating housing. The checking poppet is oriented with its actuating stem, concentric guide, and concentric force bias spring downstream of the check flow controlled orifice. In a preferred embodiment, the flow control assembly is located internal of a housing having a first flow length adjacent the controlled flow orifice and seat. A second converging flow length abuts the first flow length and a terminating flow outlet is adjacent the valve outlet port.
Shortcomings of the prior art spring and poppet designs include the requirement that the article be fabricated from a number of different components and which, upon being assembled together and installed within the desired valve housing (e.g., pressure relief, check or the like) increases the incidences of breakage or failure. This shortcoming is particularly evident in environmentally challenging (caustic) environments, and in particular in aviation applications and wherein failure of a valve assembly can be particularly dangerous.